The UK's most complete GLP-1 guide
Every Question Answered. Every Side Effect Explained.
- How GLP-1 medications work
- Mounjaro vs Wegovy compared
- Injection instructions
- Side effects & solutions
- What to eat on treatment
- FAQs answered
Free tracker included with every download this week
Weight Per Age Chart — What's a Healthy Weight for Your Age?
There's no single "ideal" weight for a specific age — healthy weight depends on your height, body composition, and individual health. However, the NHS uses BMI (body mass index) to determine whether a weight falls within a healthy range, regardless of age. This guide explains how to assess healthy weight for UK adults and why age alone isn't the best measure. Use our free BMI calculator and weight converter to find your personal healthy weight range based on your height.
10,000+ calculations today · NHS-aligned thresholds · 100% free
Calculate Your BMI Instantly
Enter your height and weight below. Supports both imperial (stone & lbs) and metric (kg). Results include NHS category, healthy weight range, and ethnicity adjustments.
What Is BMI and Why Does It Matter?
Body Mass Index (BMI) is the most widely used screening tool for assessing whether your weight falls within a healthy range. Used by the NHS, GPs, and weight management services across the UK, BMI provides a quick snapshot of your weight relative to your height. The formula is simple: your weight in kilograms divided by your height in metres squared (kg/m²).
While BMI isn't a perfect measure — it doesn't account for muscle mass, bone density, or fat distribution — it remains the standard first step in identifying potential weight-related health risks including type 2 diabetes, cardiovascular disease, high blood pressure, and certain cancers.
The NHS also recommends adjusted thresholds for people of South Asian, Chinese, or Black African heritage — a BMI of 23 or above is classified as overweight, and 27.5 as obese. Our calculator includes this adjustment as a one-click toggle.
Why Age Alone Doesn't Determine Healthy Weight
A common misconception is that there's a standard weight everyone should be at a particular age. In reality, healthy weight varies enormously based on height, sex, muscle mass, bone density, and overall health status — not age. The NHS guidance focuses on BMI rather than age-based charts because BMI accounts for how weight relates to height.
For example, two 45-year-old women of the same height could both have healthy weights within the same BMI range (18.5–24.9), but actual weight might differ by 10kg depending on muscle mass. Similarly, a 65-year-old man might have the same healthy weight range as a 30-year-old man of identical height. Age itself is less important than these individual factors.
That said, metabolism does slow slightly with age, and muscle mass naturally decreases after 30, which can make weight management slightly more challenging. But this doesn't change the BMI thresholds used for healthy weight assessment across the UK.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
How It Works
Three simple steps to understand your weight and take action.
Enter your height and weight in our free calculator. Get your BMI, NHS category, healthy weight range, and ethnicity-adjusted thresholds instantly.
If your BMI suggests you're overweight or obese, explore our GLP-1 calculators to project potential weight loss on Mounjaro or Wegovy.
Use our progress tracker to log your weight weekly, visualise your journey with charts, and stay motivated — all stored privately in your browser.
Free Weight Loss Tools & Guides
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
NHS BMI Categories — The Standard Across All Ages
The NHS uses the same BMI categories for all adults aged 18 and over, regardless of age:
- Healthy weight: BMI 18.5–24.9
- Overweight: BMI 25–29.9
- Obese: BMI 30 and above
To find your healthy weight range for your height, use our free BMI calculator above. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds — healthy weight starts at BMI 18.5–22.9. Your GP can advise if your current weight is appropriate for your individual health. Weight management works best alongside regular physical activity and balanced nutrition at any age.
- Dual GIP/GLP-1 receptor agonist
- Up to 22.5% body weight loss (SURMOUNT-1)
- Weekly injection, dose escalation over 20+ weeks
- Available via private prescription in the UK
- Doses: 2.5mg → 5mg → 7.5mg → 10mg → 12.5mg → 15mg
- GLP-1 receptor agonist
- Up to 15–17% body weight loss (STEP trials)
- Weekly injection, 5-step dose escalation
- NHS & private prescription available
- Doses: 0.25mg → 0.5mg → 1mg → 1.7mg → 2.4mg
Mounjaro vs Wegovy: Head-to-Head
A side-by-side comparison of the two most popular GLP-1 weight loss medications available in the UK.
| Feature | Mounjaro | Wegovy |
|---|---|---|
| Drug class | Dual GIP/GLP-1 agonist | GLP-1 agonist |
| Active ingredient | Tirzepatide | Semaglutide |
| Avg. weight loss | 15–22.5% | 12–17% |
| Key trial | SURMOUNT-1 (2022) | STEP 1 (2021) |
| Max dose | 15 mg weekly | 2.4 mg weekly |
| Escalation period | 20–32 weeks | 16–20 weeks |
| Administration | Weekly injection (pen) | Weekly injection (pen) |
| NHS availability | Private prescription only | NHS & private |
| Approx. private cost | £150–£250/month | £150–£300/month |
| Common side effects | Nausea, diarrhoea, constipation | Nausea, vomiting, diarrhoea |
Data sourced from SURMOUNT-1 and STEP 1 clinical trials. Costs are approximate and vary by provider. Always consult a prescriber.
Am I Eligible for Weight Loss Medication?
In the UK, eligibility for GLP-1 weight loss medications like Mounjaro and Wegovy is based on your BMI and overall health profile.
- BMI of 30 or above (obese)
- Age 18 or over
- No contraindicated conditions
- Committed to lifestyle changes
- BMI of 27 or above
- Plus type 2 diabetes
- Or high blood pressure
- Or obstructive sleep apnoea
Use our BMI calculator to check whether your BMI falls within the eligible range.
How We Built These Tools
Every calculator and guide on myweightcheck is built with accuracy and transparency in mind. Our BMI calculator uses the standard WHO formula with NHS-aligned category thresholds. Our GLP-1 projections are modelled on published clinical trial data from SURMOUNT and STEP studies.
All data stays on your device. We don't require sign-ups, and we don't store your health information on any server. Your progress tracker saves data locally in your browser using localStorage, so only you can see it.
We're based in the UK and our tools are designed specifically for UK users — supporting stone & lbs by default, referencing NHS guidelines, using NICE-approved medication data, and linking to GPhC-registered pharmacies.
Frequently Asked Questions
Common questions about BMI, weight loss medications, and our free UK tools.
Is there a healthy weight chart based on age?
No. The NHS doesn't provide age-based weight charts for adults. Instead, BMI (calculated from height and weight) is used to assess healthy weight across all adults aged 18+, regardless of age. Your healthy weight range depends on your height, not your age. Use our BMI calculator to find your personal range.
What's the average weight for UK adults by age?
According to recent data, the average UK adult man weighs approximately 85.7kg (13st 7lbs) and the average woman weighs approximately 71.6kg (11st 3lbs). However, "average" is not the same as "healthy." Many UK adults are overweight or obese, so average weight often exceeds healthy weight ranges. Your GP can advise on what's healthy for you personally.
Does metabolism slow down with age, affecting healthy weight?
Yes, metabolism slows slightly and muscle mass naturally decreases after age 30. This can make weight management slightly more challenging with age. However, the BMI healthy weight range remains the same — a 65-year-old and a 35-year-old of the same height have the same healthy BMI range. Regular activity and balanced nutrition help maintain healthy weight at any age.
How do I find my healthy weight range?
Use the free BMI calculator on this page, entering your height and current weight. The calculator will show you whether you're in the healthy, overweight, or obese range according to NHS guidelines. You can also use our weight converter to switch between kg, stone, and pounds. If you're concerned about your weight, speak to your GP for personalised advice.
Are BMI thresholds different for older adults?
No. The NHS uses the same BMI categories (18.5–24.9 for healthy weight) for all adults aged 18 and above, including older adults. However, BMI has limitations for elderly people with significant muscle loss. Your GP can assess whether BMI alone is appropriate for your health or whether other measurements like waist circumference should be considered. ```
Ready to take control of your weight loss journey?
Start with a free BMI check, explore your GLP-1 options, or begin tracking your progress today. No sign-up. No cost. Just results.